jquery select change цена

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<span class="product-price" itemprop="price" id="price">$299.00</span>
<label>Magnification</label>
<select class="product-variants readers" id="readers" name="readers">
           <option data-price="0" value="0">None</option>
    <option data-price="40" value="+2000.50">+1.50</option>
     <option data-price="40" value="+2.00">+2.00</option>                   
    <option data-price="40" value="+2.50">+2.50</option>
</select>
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Anxious Aardvark